This invention relates to an end structure of a surface material of a vehicle seat cushion which is disposed on lower rails in a vehicle so as to be slidable in the forward and backward direction of the vehicle.
A conventional vehicle seat cushion is illustrated as a fragmentary cross-sectional view in FIG. 1. The conventional vehicle seat cushion S which comprises a frame 1 formed of a resin or a metallic material, springs 2 stretched inside the frame 1, a cushioning material 3 such as foamed polyurethane positioned over the frame 1 and the springs 2, and a surface material 4 covering the surface of the cushioning material 3. The surface material 4 consists of plural pieces of cloth sewed together in the form of a bag, and it has an end portion 5 which inwardly extends along the bottom of the seat cushion S and fixed via worm clips 6 or the like to holes 7 formed through the frame 1. To the bottom face of the seat cushion S there are fixed upper rails 8 which are slidably positioned on their corresponding lower rails (not shown), the upper rails 8 being fixed with screws or the like (not shown) to the frame 1 with the surface material 4 interposed therebetween.
However, a vehicle seat cushion having the aforesaid construction has a drawback such that, since the upper rails 8 are fixed onto the end portion 5 of the surface material 4, the pressure of the upper rails 8 is exerted on the end portion 5 during the use of the seat cushion over a long period of time and this pressurized portion m may be cracked resulting in the end portion 5 being split off at the crack. It has further drawbacks, for example, when mounting the upper rails 8, a jig or the like for mounting the upper rails 8 may strike against and damage the end portion 5, or since it is required to form holes through the end portion 5 for the insertion of mounting screws for the upper rails 8, the end portion 5 may be torn from those holes when an excessive pulling force is exerted thereon.
It might be one solution to the above problems of conventional seat cushions to fix the end portion 5 of the surface material 4 to the outermost periphery l of the frame 1 so that the end portion 5 does not extend inwardly between the upper rails 8 and the frame 1. This method is, however, accompanied by another drawback that, since each worm clip for fixing the end portion 5 is positioned on the outer peripheral side l, it is visible from the outside, thus undesirable from the aesthetic standpoint.